Can't able to add favorite list using sharedpreference

Question

here is the error

Process: com.example.sonu.travelfreak, PID: 15374 java.lang.NullPointerException at com.example.sonu.travelfreak.PlaceView$1.onClick(PlaceView.java:42) at android.view.View.performClick(View.java:4438) at android.widget.CompoundButton.performClick(CompoundButton.java:100) at android.view.View$PerformClick.run(View.java:18422) at android.os.Handler.handleCallback(Handler.java:733) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5001) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601) at dalvik.system.NativeStart.main(Native Method)

class which add favorite

public class PlaceView extends AppCompatActivity{
TextView textView1;
TextView textView2;
ToggleButton toggleButton;
SharedPreference sharedPreference;
@Override
protected void onCreate(final Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.place_view);

    textView1= (TextView) findViewById(R.id.textViewActivity);
    textView2= (TextView) findViewById(R.id.detail);
    Intent intent=getIntent();
    final Bundle bundle=intent.getExtras();
    textView1.setText(bundle.getString("Activity"));
    textView2.setText(bundle.getString("Detail"));
   toggleButton= (ToggleButton) findViewById(R.id.toggleButton1);

    toggleButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if(toggleButton.isChecked()){
                Log.d("check",bundle.getString("position name"));
                Toast.makeText(getApplicationContext(),
                        "Added as favorites",
                        Toast.LENGTH_SHORT).show();
                sharedPreference.addFavorite(getApplicationContext(),bundle.getString("position name"));

        }
            else{

                }

            }


    });

}

}

class which set value for each row of recyclerview

public class fav_info {
String string;
public String getname(){
    return string;
}
public void setname(String name){
    this.string=name;
}}

sharedpreference class which handle add,remove,save favorites

 import android.content.Context;
 import android.content.SharedPreferences;
 import android.content.SharedPreferences.Editor;
 import com.google.gson.Gson;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
public class SharedPreference {
public static final String PREFS_NAME = "PRODUCT_APP";
public static final String FAVORITES = "Product_Favorite";

public SharedPreference() {
    super();
}


public void saveFavorites(Context context, List<fav_info> favorites) {
    SharedPreferences settings;
    Editor editor;

    settings = context.getSharedPreferences(PREFS_NAME,
            Context.MODE_PRIVATE);
    editor = settings.edit();

    Gson gson = new Gson();
    String jsonFavorites = gson.toJson(favorites);

    editor.putString(FAVORITES, jsonFavorites);

    editor.commit();
}

public void addFavorite(Context context, String string) {
    fav_info fi=new fav_info();
    fi.setname(string);
    List<fav_info> favorites = getFavorites(context);
    if (favorites == null)
        favorites = new ArrayList<fav_info>();
    favorites.add(fi);
    saveFavorites(context, favorites);
}

public void removeFavorite(Context context, fav_info fav_info) {
    ArrayList<fav_info> favorites = getFavorites(context);
    if (favorites != null) {
        favorites.remove(fav_info);
        saveFavorites(context, favorites);
    }
}

public ArrayList<fav_info> getFavorites(Context context) {
    SharedPreferences settings;
    List<fav_info> favorites;

    settings = context.getSharedPreferences(PREFS_NAME,
            Context.MODE_PRIVATE);

    if (settings.contains(FAVORITES)) {
        String jsonFavorites = settings.getString(FAVORITES, null);
        Gson gson = new Gson();
        fav_info[] favoriteItems = gson.fromJson(jsonFavorites,
                fav_info[].class);

        favorites = Arrays.asList(favoriteItems);
        favorites = new ArrayList<fav_info>(favorites);
    } else
        return null;

    return (ArrayList<fav_info>) favorites;
}}

ya i have missed that nyway thnx – sonu kumar prashant Jul 03 '16 at 06:32 — sonu kumar prashant, Jul 03 '16 at 06:32

score 0 · Answer 1 · answered Jul 01 '16 at 16:02

You have to instantiate the SharedPreference class before using it's object

so add this line before accessing sharedPreference object,

SharedPreference sharedPreference = new SharedPreference();

I think you forgot to add this line..

Note: in your code you have declared SharedPreference as a class attribute, so following line would be fine,

sharedPreference = new SharedPreference();

Thanks

Can't able to add favorite list using sharedpreference

1 Answers1